Have any of you utilized CMM-equipped temp compensation (using the probe affixed to your part) with success before? I've been lucky for the past 10 years and had well controlled environmental conditions.
Now, I've got 3 cmm's which share the same HVAC as >20 injection molding presses... We see one daily, predictable -and thankfully slow- temp shift of about 9°F. It only has potential to affect one dimension on one of our many parts, with a potential shift of .0022" along a 5" long polypropylene tube (potentially consuming 11% of the 0.020" tolerance).
Sorry for hijacking, just seemed like a perfect spot to do it, lol.
If the part is ferrous it could work OK as the probe has a magnet in it. If it's a non-ferrous material then you'll need a way to keep the probe against the part for 5 to 10 minutes. The probe takes a fairly long time to read the temperature. What I've done is every couple of minutes hit F9 on the temp comp code to pull up the window and click update temp to see what it's reading. Once it stops moving you'll be good to go.
The other option is change it to allow you to input the temperature from a hand held device, if you have one. That's especially good if you have a calibrated gage.
I don't know if this was addressed, but the CMM itself will also expand/contract at the same time as your Inconel, but by a different amount. Unless it is ALL made of the same material, it may very well expand/contract differently in X/Y/Z, too! Knowing CTE of the target is only half of the problem. I am in an uncontrolled environment, as well, but have Temp Comp in the S/W, plus sensors on all 3 axes AND another sensor to stick to the target. It is probably a very complicated calculation, but the S/W does it. I would tend to not trust it (I am a very untrusting soul...) if it is more than like 15-degrees (F) from 68. At the very least, that philosophy saves me lots of work on the hottest days. Before we had Temp Comp, we had a tool standard. I long tool made of aluminum (much of what we CMM is aluminum) that has been outside-certified for length. As it got hotter (or colder), we would measure the length of the tool (both parallel to X and then Y), and compare that length to the certified length. That would give us a weird CTE (our CTE rolled the CTE of the target and the CTE of the CMM all into one Franken-number) that we recorded on paper. We ended up with a table of 'CTE' at each degree between about 60 and 90 degrees. It only worked for aluminum, though. TPTB didn't want to spring for another tool standard made out of Inconel, or for steel, or for titanium.
